Comments on: O Level Chemistry Question – Preparation of Salts

By: yi en

yi en — Tue, 05 May 2009 02:26:04 +0000

Copper sulphate is soluble. So you can either prepare it using titration or crystallisation. Crystallisation is easier and it has lesser steps than titration.
A is wrong as the two salts would not react at all.
B is correct
C is wrong as copper is an unreactive metal and the reaction would not occur
D is wrong as the two salts would not react.

So B is correct right?

By: dreamsforeva

dreamsforeva — Thu, 01 Nov 2007 08:24:00 +0000

its B!

C is out cos copper is unreactive.
as for A, both the products are aq which makes it difficult to seperate them.

For B, sulphuric acid and excess of insoluable copper carbonate to ensue that all of the acid is used up.

since the excess copper carbonate is insoluable, it can easily be filtered out.
the pure filtrate is then evaporated to dryness to obtan pure cuso4 crystals.

there!

By: Anonymous

Anonymous — Tue, 23 Oct 2007 03:33:00 +0000

It A la….u all know y? because in order to produce a salt both substance must be in aqueous form…..

By: Sean Chua

Sean Chua — Sat, 20 Oct 2007 17:10:00 +0000

Ruth is right!

Copper being a very unreactive metal will tends to form very unstable (thus reactive)compounds with other element(s).

Copper (II) carbonate is not a very stable compound of Cu and thus tends to react with the H2SO4 based on the word equation below.

Answer should be B.

PS: The only soluble carbonates are SPA - Sodium, Potassium and Ammonium carbonates.

Sean
SimpleChemConcepts
"Learning Experience with A Difference"

Copper(II) carbonate + sulphuric acid ==> copper(II) sulphate + water + carbon dioxide

By: ruth

ruth — Sat, 20 Oct 2007 03:00:00 +0000

Weeeell, A isn't wrong per say cause you will get copper(II) sulphate. Yes, they are both soluble salts which means that you'll find that they deionise in water to form ions(duh, lol).
Thus, some of the ions will bond to form copper(II) sulphate but it isn't a very effective method ^ ^
For the pure copper and acid reaction, there won't be any reaction at all since copper's less reactive than hydrogen and won't be able to displace it.
And yeah well, the answer should be copper carbonate and the acid. See right, the rule of thumb is that since copper is low down in the reactivity series, it doesn't like staying as a salt and will decompose easily. Thus when you react it with acid, it'll easily form copper(II) sulphate, water and carbon dioxide.
The last two are just bases so, no reaction as lots of you have said(:

AND AND copper carbonate is insoluble. The only soluble carbonates are sodium carbonate, potassium carbonate and ammonium carbonate.